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以Calyculin A诱导早熟染色体凝聚(PCC)方法,探索G2/M-PCC细胞中PCC环用于分析电离辐射损伤程度的可行性,用0—20 Gy(剂量率为1 Gy/min)的60Coγ射线照射外周血,培养48 h并用Calyculin A诱导PCC。分析各剂量点G2/M-PCC指数、判断观察到的PCC环是否符合泊松分布,建立PCC环率与剂量之间的剂量效应曲线。结果发现,用Calyculin A可成功诱导人外周血淋巴细胞产生PCC,且G2/M-PCC指数随着剂量水平的增高而降低。除20 Gy剂量外,0—16 Gy各剂量点样品中PCC环的分布符合泊松分布。PCC环率随着剂量增加而增加,剂量-效应曲线可以拟合成y=0.0128x+0.0104直线方程,测得R2=0.9898(y为PCC-R率,x为剂量);二次多项式方程为y=0.00002x2+0.0085x+0.0011 R2=0.9996。由此可见,Calyculin A诱导淋巴细胞G2/M-PCC中的PCC环率可用于生物体电离辐射损伤程度测定。 相似文献
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冈田酸诱导早熟染色体凝聚的辐射剂量效应关系研究 总被引:1,自引:0,他引:1
为研究冈田酸(Okadajc acid)诱导的染色体凝聚与辐射剂量之间的剂量效应关系,采用不同剂量(0、0.5、1.0、2.0、3.0和5.0Gy)的X射线照射离体人外周血,培养48b,终止培养前2 h加入Okadaic acid诱导早熟染色体的凝聚,观察分析其诱导的早熟凝聚染色体(Prcrnaturc condensed chromosome,PCC)的断片率,并与常规染色体畸变分析法进行比较.结果表明,冈田酸诱导的早熟染色体凝聚方法与常规染色体法相比可获得更高的分裂指数,冈田酸法染色体凝聚断片率与外照射剂量之间存在良好的线性关系. 相似文献
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研究用熟前染色体凝集(PCC)技术观察了~(60)Co-γ射线诱发人淋巴细胞熟前凝集染色体断片的剂量效应关系。同时与常规细胞遗传学方法作比较,获得了两者的效应(Y)、剂量(D)线性方程。两者曲线方程斜率比K_(PCC)/K_(M_1)≈28。结果表明,PCC技术与常规细胞遗传学方法相比有快速、简便、灵敏、准确等优点。并讨论了PCC技术在辐射损伤研究中的意义。 相似文献
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染色体畸变分析可作为一种估算受照剂量,评价辐射损伤的生物学方法。本文采用G 显带方法对两名健康男性外周血淋巴细胞离体照射后的染色体畸变进行核型分析,对染色体断裂点分布进行了初步研究;并和常规法结果进行比较,以了解显带方法是否有助于提高畸变细胞的检出率。 相似文献
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核工业系统辐射细胞遗传学研究二十年 总被引:1,自引:0,他引:1
由于核工业生产和发展的特点,辐射防护中的生物剂量估计的研究工作,一直受到较大的重视.自1972年以来,核工业系统的几个单位(中国辐射防护研究院、中国原子能科学研究院、苏州医学院和安防局所属的一些医院)相继开展了这方面的研究工作.本文概述了上述各单位的绝大部分研究成果.用估计染色体畸变分析法进行的生物剂量的研究是主要的.70年代初致力于方法的建立和改进的研究,证明培养对同的长短对染色体畸变率有较大影响,结果表明应缩短培养时同,以后的进一步工作表明,用FPG法比常规Giemsa染色法的染色体畸变率更接近真实的情况.对正常人群(职工)自发染色体畸变率的调查表明,其数值为0.31-0.34%之间,与国内其他主要单位调查结果相符;正常农民组的染色体畸变本底值则较低.70年代期间,曾用常规Giemsa法建立了由γ、X、中子及β射线照射人淋巴细胞诱发染色体畸变的剂量效应曲线;80年代应用FPG法建立了由γ、X、中子、电子束和~3H-β射线照射诱发染色体畸变的剂量效应曲线,并应用它们对受过量照射人员进行了生物剂量估计,为受照剂量的总体估计及为医治措施制订提供依据.初步的结果显示,畸变率的高低似与个人累积剂量值有直线相关关系.其他的细胞遗传学方法(微核、SCE、PCC)进行的研究表明,淋巴细胞微核法,特别是用改进的加入松胞素B微核法,在生物剂量估计方面,仍是一个有效的方法.在测得正常人群微核率本底值后,建立了经x、X射线和电子束照射诱发微核率的剂量效应曲线,用微核法对事故受照人员作剂量估计与用染色体畸变率估计的基本一致.用SCE法:对受辐照者与对受化学因素影响者检测,结果表明该法对受照射人员不是一个敏感指标.对早熟染色体凝聚技术(PCC)的研究表明,本指标较之染色体畸变分析的敏感性要高得多.实际应用中,需要对影响条件和因素进行系统的探索. 相似文献
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用^60Co产生的γ射线照射人肝癌细胞系SMMC-7721.以克隆形成法测定经照射后的细胞存活率,用化学诱导剂Calyculin-A诱导的早熟染色体凝集(Premature chromosome condensation,PCC)技术研究染色体损伤.结果显示G2期细胞内的染色单体和等点染色单体断裂数与照射剂量之间存在着线性相关性,染色单体断裂数与细胞存活率之间存在较好的线性相关性.表明辐射诱导的染色单体断裂可以作为预测SMMC-7721细胞内在辐射敏感性的指标,也可为临床诊断和治疗肝癌提供依据. 相似文献
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小剂量慢性照射诱导小鼠生殖细胞适应性反应的初步研究 总被引:1,自引:1,他引:0
采用小剂量^137Cs γ射线慢性整体照射雄性小鼠,分别于D1照后24h,30d给予较大剂量X射线照射,通过分析其初级精母细胞的染色体畸变,观察预先小剂量照射对第二次大剂量照射损伤的影响。结果表明,小剂量γ射线预先照射能够明显降低随后大剂量照射所致的染色体损伤,即诱导了小鼠生殖细胞的适应性反应。 相似文献
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染色体畸变分析用于离体模拟与活体局部照射剂量估计的实验研究 总被引:1,自引:1,他引:0
用不纯泊松分布方法,分析新西兰兔离体模拟与活体局部照射后的染色体畸变数据,以检验该法用于局部照射事故生物剂量估计的可能性。为此,首先建立了畸变率与剂量的关系曲线,研究了照射对 于受照淋巴细胞进入中其分裂的几率的影响。兔血经^6^0Coγ射线离体照射1-9Gy后进行两类增养:(a)培养纯受照血(b)将70%的受照血与30%的正常血混合,培养混合血。实验结果表明:(1)兔血照射后的双着粒畸变率与剂量成 相似文献
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LIU Xiuhua XU Yunshu ZHONG Zhijing FU Yibei DENG Yi 《核技术(英文版)》2007,18(1):59-64
Zn-doped TiO2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis, BET, XRD in this study. Under the irradiation of simulant sunlight, the photocatalytic activity for the degradation of p-nitrophenol was studied too. After irradiation for 2.5 h, the degradation percentage of p-nitrophenol could rise to more than 80 %. The results showed that the spectrum absorption band edge of Zn/TiO2 powder does not broaden obviously comparing with pure TiO2 powder. Zinc exists as Zn (11). When calcined at 973 K, there is a new phase as ZnTiO3 in Zn/TiO2 catalyst. The order of photocatalytic activity of Zn/TiO2 catalysts calcined at different temperatures for p-nitrophenol is 773 K 〉 673 K 〉 873 K 〉 573 K 〉 973 K and the photocatalytic activity of Zn/TiO2 catalyst calcined at 773 K is better than TiO2 catalysts heated at the same temperature, and outclasses that of commercial TiO2 catalyst. It also showed that the photocatalytic degradation of p-nitrophenol follows first-order kinetics under the irradiation of simulant sunlight. 相似文献
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FU Shen SUNYi LU Yaohong 《核技术(英文版)》2007,18(2):65-72
Radiotherapy for the treatment of prostate cancer has been extensively explored in the past. Along with the comprehensive understanding of the biology of prostate cancer and rapid advances in terms of technology, the out- come of treatment for the patients with prostate cancer has improved. The authors review radiotherapy as the primary treatment for the disease, with particular emphasis on the technological advances from both the radiobiological and radiophysics aspects. Nonconventional fractionated irradiation like hyper- or hypo-fractionation has been imple- mented in the clinic, the final results still need to be confirmed in the future. Technological advances like IMRT, IGRT, in the last two decades have significantly improved the delivery of external radiotherapy to the prostate. This has re- sulted in an overall increase in the total dose that can be safely delivered to the prostate, which has led to modest im- provements in the biochemical outcome. However, establishing the standard therapy for prostate cancer remains con- troversial. It is hoped that the next decades will bring continued advances in the development of biologicals that will further improve current clinical outcomes. 相似文献
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This paper introduces the injection and extraction control system design for SSRF,which is a distributed control system aimed at stability and reliability of the pulse power supplies,PPS(Personnel Protection System)and MPS(Machine Protection System).The hardware environment is mainly based on PLC(Programmable Logic Con- troller),and ARM(Advanced RISC Machine)is also applied for studying stability of the power supplies.WinCC and EPICS(Experimental Physics and Industrial Control System)have been selected as the platforms of SCADA(Super- visory Control and Data Acquisition).For unifying the interfacing to the control computer,all front-end equipments are connected via Industrial Ethemet. 相似文献
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为研究含空气蒸汽在水平管内强制对流冷凝换热特性,基于对传热传质过程的分析,建立了管内为环状流与波状流条件下的流动冷凝换热模型。从潜热、显热和液膜3个环节对整个换热过程进行建模,最终得到计算局部冷凝换热系数的理论关系式。模型预测结果与实验数据的对比表明,二者相对偏差在±20%以内,验证了该换热模型的准确性与适用性。通过进一步的研究发现:从换热管入口至出口,随着冷凝的进行,管内换热主要热阻由液膜热阻向气液界面的凝结热阻转变;主流气体对流换热过程基本可忽略。 相似文献
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D.Rezaei OCHBELAGH H.Miri HAKIMABAD R.Izadi NAJAFABADI 《核技术(英文版)》2007,18(4):237-241
Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and its shield play an important role. In this paper, the effects of graphite, heavy water, polyethylene and boric acid moderators on the flux of back scattered neutrons were investigated. We have also experimentally verified the effect of BF3 detector shield and obtained good agreement with theory. 相似文献
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LI Lin SHEN Liren ZHU Qing WAN Tianmin 《核技术(英文版)》2007,18(4):193-197
Accelerator database stores various static parameters and real-time data of accelerator. SSRF (Shanghai Synchrotron Radiation Facility) adopts relational database to save the data. We developed a data retrieval system based on XML Web Services for accessing the archive data. It includes a bottom layer interface and an interface applicable for accelerator physics. Client samples exemplifying how to consume the interface are given. The users can browse, retrieve and plot data by the client samples. Also, we give a method to test its stability. The test result and performance are described. 相似文献
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为对自制的活性面积高达1 000 cm2的大面积源进行表面发射率定值,同时作为现有2πα、2πβ表面发射率标准装置能力的扩充,研制了一套内置式大面积2π多丝正比计数器测量系统,并利用活性区直径为8 mm的241Am点源及活性区面积为10 cm×15 cm的大面积241Am和90Sr-90Y源对其进行计量学性能测试。结果表明:计数器内计数响应均匀性优于±0.4%,有效探测面积达1 400 cm2;所得241Am源高压坪曲线的坪长为1 400 V,坪斜为0.27%/100 V,坪区内计数变化为0.87%;90Sr-90Y源高压坪曲线的坪长为300 V,坪斜为0.75%/100 V,坪区内计数变化为0.80%;10次测量重复性好于0.4%,8 h内短期稳定性好于0.3%,1 a内长期稳定性好于0.8%。 相似文献
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Distributions of natural gamma-emitting radionuclides were determined in 93 oil samples collected from some petroleum fields in the western desert of Egypt. The radioisotope activities in the area under investigation lay in the range of (21 ± 4) to (38 ± 13) Bq?L-1 for 226Ra, (9 ± 2) to (15 ± 5) Bq?L-1 for 232Th, and (154 ± 28) to (303 ± 54) Bq?L-1 for 40K. The mean values were 27, 12, and 201 Bq?L-1, respectively. Among oils, variations in radionuclide ac- tivities could be on account of differences in TDS, HCO3, and Ba, with high or low pH. In this environment, oil prop- erties differently affected the mobilization of natural radionuclides. The range of 226Ra variation had been compared with available data from other countries. The calculated absorbed dose rate ranged from 22.33 to 32.66 nGy?h-1 in lo- cation (B) and (E) respectively, which was less than the accepted value. 相似文献
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In this work,TTHMP was synthesized and labelled with 117m Sn.The preparation conditions,stability and lipophilicity of 117m Sn(IV)-TTHMP were investigated.Biodistribution of the complex in rabbits and mice was studied.It was found that the quantity of TTHMP and pH value of the prepararion solution had vital effects on the labeling yield of 117m Sn(IV)-TTHMP.It was also found that 117m Sn(IV)-TTHMP was hydrophilic and stable at room temperature and 37℃ in open air 117m Sn(IV)-TTHMP showed unexpectedly high bone uptake and bone-to-blood ratio in the animals.This made it potentially useful as an reagent for skeletal scintigraphy and radiotherapy of bone tumors. 相似文献
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LI Zhaobin XIONG Fei HUANG Guofeng CAO Zheng JIANG Ruiyao FU Shen 《核技术(英文版)》2007,18(3):145-149
Linear accelerators equipped with multileaf collimators (MLC) are becoming more common and are widely used in the intensity-modulated radiotherapy (IMRT). There is an imperative need to ensure the commissioning specification of the linear accelerators for the sake of quality assurance (QA) and quality control (QC). This paper is aimed to investigate the role of AGFA high-energy CR (Computed Radiography) in calibrating dynamic multileaf collimators and evaluating the accuracy of the leaf position. The result shows that AGFA high-energy CR can easily and conveniently be used to calibrate MLC and verify its position. Hence, the application of AGFA high-energy CR is proved to be an accurate and time-saving method for routine MLC QC, especially when MLC calibration adjustments are required. 相似文献